Cushioning materials have a variety of uses, such as for mattresses, seating surfaces, shoe inserts, packaging, medical devices, etc. Cushioning materials may be formulated and/or configured to reduce peak pressure on a cushioned body, which may increase comfort for humans or animals, and may protect objects from damage. Cushioning materials may be formed of materials that deflect or deform under load, such as polyethylene or polyurethane foams (e.g., convoluted foam), vinyl, rubber, springs, natural or synthetic fibers, fluid-filled flexible containers, etc. Different cushioning materials may have different responses to a given pressure, and some materials may be well suited to different applications. Cushioning materials may be used in combination with one another to achieve selected properties.
U.S. Pat. No. 7,730,566, issued Jun. 8, 2010, and entitled Multi-Walled Gelastic Material, the disclosure of which is incorporated herein in its entirety by this reference, describes cushion structures having interconnected walls that buckle. A first wall buckles when a threshold force is applied. Buckling of the first wall may cause buckling of a second wall, which may decrease the chance that the first wall will “bottom out.” Bottoming out would increase pressure on the portion of the cushioned object over the buckled portion of the cushion. One side of the cushion has walls spaced relatively close together, and the opposite side has walls spaced farther apart. That is, some walls of the cushion extend only partially through the cushion. The wider-spaced portions of the walls may buckle more easily than the closer-spaced portions of the walls when an irregularly shaped object presses against the walls.